LINQ to Entities ne reconnaît pas la méthode 'System.Decimal Parse(System.String)'

Question

In my SQL SERVER I have a field Poids (type: Varchar) and when I tried to convert it to Decimal I had this error: "LINQ to Entities ne reconnaît pas la méthode 'System.Decimal Parse(System.String)'" . This my code:

  var list = db.Réception.Where(y => y.Supprimée == false).
                Select(x => new
                {
                    Id_rec = x.Id_rec,
                    N° = x.N°,
                    Date_rec = x.Date_rec.ToString(),
                    heure_rec = x.heure_rec.ToString(),
                    Qualité = x.Qualité.Qualité1,    
                    Poids = x.Wg.AsEnumerable().Where(y => y.Id_rec == x.Id_rec).Select(w => decimal.Parse(w.Poids)).Sum(),
                    Nbwg =x.Wg.Where(y => y.Id_rec == x.Id_rec).Count()    
        });

Please if someone can help me I'm blocked and I tried some solutions in web but without results.